Apparatus and methods for optimization of powder removal features in additively manufactured components

ABSTRACT

Techniques for optimizing powder hole removal are disclosed. In one aspect, an apparatus for inserting powder removal features may identify what powder removal features are optimal for a given AM component, as well as the optimal location and physical characteristics of these features. The features are automatedly added to the component, and an FEA test is run. In the event of failure, the offending feature is removed and the process is repeated. If successful then the loose powder may be removed in a post-processing step following AM.

CROSS-REFERENCE TO RELATED APPLICATION

This Application is a division of, and claims the benefit of and rightof priority to, U.S. patent application Ser. No. 15/702,543, filed Sep.12, 2017, entitled “APPARATUS AND METHODS FOR OPTIMIZATION OF POWDERREMOVAL FEATURES IN ADDITIVELY MANUFACTURED COMPONENTS”, pending, thecontents of which are incorporated by reference as if fully set forthherein.

BACKGROUND Field

The present disclosure relates generally to techniques for additivemanufacturing, and more specifically to powder removal techniques inadditively manufactured components.

Background

Additive Manufacturing (AM), commonly known as three-dimensional (3-D)printing, involves the use of a stored geometrical model foraccumulating layered materials on a ‘build plate’ to produce a 3-Dobject having features defined by the model. AM techniques are capableof printing complex components using a wide variety of materials. Asolid 3-D object can be fabricated based on a computer aided design(CAD) model.

AM processes such as powder bed fusion (PBF) use a laser or electronbeam to melt and fuse together cross-sections of the layers of powderedmaterial. The melting bonds the powder particles together in targetedareas of each layer to produce a 3-D structure having the desiredgeometry. Different materials or combinations of material, such asengineering plastics, thermoplastic elastomers, metals, and ceramics maybe used in PBF to create the 3-D object.

After a structure is additively manufactured, a significant amount ofloose powder can remain scattered and embedded within the structure. Toaddress this problem, designers manually designate holes in CAD modeledstructures. The holes placed in the data model are then physically builtinto the AM structure and used to extract the residual powder from thestructure after the AM process. This process, however, is manuallyintensive and therefore inefficient. Further, the manual hole placementprocess, which involves at least partial guesswork, may not produceoptimal powder removal configurations. For example, such manualplacement may lead to inadvertent placement of holes indifficult-to-access or other undesirable portions of the structure. Ingeneral, this conventional process may involve an initial modificationof the CAD model with manual hole placement, Next, Finite ElementAnalysis (“FEA”) tests for structural integrity may take place on theCAD model, and the initial manual placement of the holes may need to bechanged to accommodate identified structural deficiencies. This processmay have to be repeated a number of times, and becomes increasinglyburdensome as the number of component types to be additivelymanufactured increases.

SUMMARY

Several aspects of techniques for automated powder removal from AMcomponents will be described more fully hereinafter with reference tothree-dimensional printing techniques.

In one aspect, a method for automatedly inserting powder removalfeatures in an additively manufactured component includes receiving amodel of a component to be additively manufactured, automatedlydetermining optimal size and location of one or more apertures in thecomponent for powder removal, and updating the model to include the oneor more determined powder removal apertures.

In another aspect, a method for removing powder from an additivelymanufactured component includes receiving a data model of the component,the component having at least one aperture, additively manufacturing thecomponent based on the data model, removing trapped powder from theadditively manufactured component using the at least one aperture, andperforming a layup process using at least one material to seal the atleast one aperture.

In another aspect, a 3-D printer includes a powder bed for storingpowder, a depositor configured to deposit successive layers of thepowder, an energy beam, a deflector configured to apply the energy beamto fuse the powder, a build plate configured to support a build piece,and a processing system configured to receive a model of a component tobe additively manufactured, determine optimal size and location of oneor more apertures in the component for powder removal, update the modelto include the one or more determined powder removal apertures, and usethe updated model to control the energy beam to 3-D print the buildpiece.

In still another aspect, an apparatus for automatedly inserting powderremoval features in an additively manufactured component is configuredto determine optimal size and location of one or more apertures in thecomponent for powder removal, and update the model to include the one ormore determined powder removal apertures.

It will be understood that other aspects of additively manufacturingtransport structures will become apparent to those skilled in the artfrom the following detailed description, wherein it is shown anddescribed only several embodiments by way of illustration. As will berealized by those skilled in the art, the techniques for automatedpowder removal from AM components are capable of other and differentembodiments and its several details are capable of modification invarious other respects, all without departing from the invention.Accordingly, the drawings and detailed description are to be regarded asillustrative in nature and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the methods and apparatuses for techniques forautomated powder removal from AM components will now be presented in thedetailed description by way of example, and not by way of limitation, inthe accompanying drawings, wherein:

FIG. 1 illustrates a conceptual flow diagram of a process for additivelymanufacturing an object using a 3-D printer.

FIGS. 2A-D illustrate an example powder bed fusion (PBF) system duringdifferent stages of operation.

FIG. 3 illustrates an exemplary embodiment of an apparatus forfacilitating powder removal from AM structures according to an aspect ofthe disclosure.

FIGS. 4A-B are a flow diagram illustrating an exemplary process forautomatedly inserting apertures and channels into a data model forremoval of powder from an AM structure based on that model.

FIG. 5 is a view of an exemplary AM structure having powder removalfeatures.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended to provide a description of various exemplaryembodiments of techniques for automated powder hole insertion andremoval techniques for AM technologies and is not intended to representthe only embodiments in which the invention may be practiced. The term“exemplary” used throughout this disclosure means “serving as anexample, instance, or illustration,” and should not necessarily beconstrued as preferred or advantageous over other embodiments presentedin this disclosure. The detailed description includes specific detailsfor the purpose of providing a thorough and complete disclosure thatfully conveys the scope of the invention to those skilled in the art.However, the invention may be practiced without these specific details.In some instances, well-known structures and components may be shown inblock diagram form, or omitted entirely, in order to avoid obscuring thevarious concepts presented throughout this disclosure.

This disclosure is generally directed to techniques for automatedinsertion of channels and apertures into modelled AM structures for usein powder removal from the actual AM structures after the structures areadditively manufactured. A variety of different AM techniques have beendeveloped or are being developed. The techniques described in thisdisclosure have broad applicability to the existing classes of AMtechnologies as well as AM techniques that are under development or thatmay be developed in the future. Examples of a certain AM class oftechnologies known as powder bed fusion are illustrated further below.

FIG. 2 is a flow diagram 100 illustrating an exemplary process of 3-Dprinting. A data model of the desired 3-D object to be printed isdesigned in software (step 110). A data model is a virtual design of the3-D object. Thus, the data model may reflect the geometrical andstructural features of the 3-D object, as well as its materialcomposition. The data model may be created using a variety of methods,including CAE-based optimization, 3D modeling, photogrammetry software,and camera imaging. CAE-based optimization may include, for example,cloud-based optimization, fatigue analysis, linear or non-linear finiteelement analysis (FEA), and durability analysis.

3-D modeling software, in turn, may include one of numerous commerciallyavailable 3-D modeling software applications. Data models may berendered using a suitable computer-aided design (CAD) package, forexample in an STL format. STL is one example of a file format associatedwith commercially available STL-based CAD software. A CAD program may beused to create the data model of the 3-D object as an STL file.Thereupon, the STL file may undergo a process whereby errors in the fileare identified and resolved.

Following error resolution, the data model can be “sliced” by a softwareapplication known as a slicer to thereby produce a set of instructionsfor 3-D printing the object, with the instructions being compatible andassociated with the particular AM technology to be utilized (step 120).Numerous slicer programs are commercially available. Generally, theslicer program converts the data model into a series of individuallayers representing thin slices (e.g., 100 microns thick) of the objectbe printed, along with a file containing the printer-specificinstructions for 3-D printing these successive individual layers toproduce an actual AM representation of the data model.

A common type of file used for this purpose is a G-code file, which is anumerical control programming language that includes instructions for3-D printing the object. The G-code file, or other file constituting theinstructions, is uploaded to the 3-D printer (step 130). Because thefile containing these instructions is typically configured to beoperable with a specific AM process, it will be appreciated that manyformats of the instruction file are possible depending on the AMtechnology used.

In addition to the printing instructions that dictate what object is tobe rendered and how that object is to be rendered, the appropriatephysical materials necessary for use by the 3-D printer in rendering theobject are loaded into the 3-D printer using any of several conventionaland often printer-specific methods (step 140). In selective lasersintering (SLS) printing, selective laser melting (SLM) and othermethods, the materials may be loaded as powders into chambers that feedthe powder to a build platform. Depending on the 3-D printer, othertechniques for loading printing materials may be used.

The respective data slices of the 3-D object are then printed based onthe provided instructions using the material(s) (step 150). In fuseddeposition modelling, as described above, parts are printed by applyingsuccessive layers of model and support materials to a substrate. Asnoted above, any suitable AM technology may be employed for purposes ofthis disclosure.

One class of AM techniques includes powder-bed fusion (“PBF”). PBF AMtechniques include, by way of example, selective laser melting (SLM),selective laser sintering (SLS), direct metal laser sintering (DMLS),electron beam melting (EBM), and selective heat sintering (SHS). LikeFDM, PBF creates ‘build pieces’ layer-by-layer. Each layer or ‘slice’ isformed by depositing a layer of powder and exposing portions of thepowder to an energy beam. The energy beam is applied to melt areas ofthe powder layer that coincide with the cross-section of the build piecein the layer. The melted powder cools and fuses to form a slice of thebuild piece. The process can be repeated to form the next slice of thebuild piece, and so on. Each layer is deposited on top of the previouslayer. The resulting structure is a build piece assembled slice-by-slicefrom the ground up.

In 3-D printers that use SLM, a laser scans a powder bed and melts thepowder together where structure is desired, and avoids scanning areaswhere the sliced data indicates that nothing is to be printed. Thisprocess may be repeated thousands of times until the desired structureis formed, after which the printed part is removed from a fabricator.

FIGS. 2A-D illustrate respective side views of an exemplary PBF system200 during different stages of operation. As noted above, the particularembodiment illustrated in FIGS. 2A-D is one of many suitable examples ofa PBF system employing principles of this disclosure. It should also benoted that elements of FIGS. 2A-D and the other figures in thisdisclosure are not necessarily drawn to scale, but may be drawn largeror smaller for the purpose of better illustration of concepts describedherein. PBF system 200 can include a depositor 201 that can deposit eachlayer of metal powder, an energy beam source 203 that can generate anenergy beam, a deflector 205 that can apply the energy beam to fuse thepowder, and a build plate 207 that can support one or more build pieces,such as a build piece 209. PBF system 200 can also include a build floor211 positioned within a powder bed receptacle. The walls of the powderbed receptacle 212 generally define the boundaries of the powder bedreceptacle, which is sandwiched between the walls 212 from the side andabuts a portion of the build floor 211 below. Build floor 211 canprogressively lower build plate 207 so that depositor 201 can deposit anext layer. The entire mechanism may reside in a chamber 213 that canenclose the other components, thereby protecting the equipment, enablingatmospheric and temperature regulation and mitigating contaminationrisks. Depositor 201 can include a hopper 215 that contains a powder217, such as a metal powder, and a leveler 219 that can level the top ofeach layer of deposited powder.

Referring specifically to FIG. 2A, this figure shows PBF system 200after a slice of build piece 209 has been fused, but before the nextlayer of powder has been deposited. In fact, FIG. 2A illustrates a timeat which PBF system 200 has already deposited and fused slices inmultiple layers, e.g., 150 layers, to form the current state of buildpiece 209, e.g., formed of 150 slices. The multiple layers alreadydeposited have created a powder bed 221, which includes powder that wasdeposited but not fused.

FIG. 2B shows PBF system 200 at a stage in which build floor 211 canlower by a powder layer thickness 223. The lowering of build floor 211causes build piece 209 and powder bed 221 to drop by powder layerthickness 223, so that the top of the build piece and powder bed arelower than the top of powder bed receptacle wall 212 by an amount equalto the powder layer thickness. In this way, for example, a space with aconsistent thickness equal to powder layer thickness 223 can be createdover the tops of build piece 209 and powder bed 221.

FIG. 2C shows PBF system 200 at a stage in which depositor 201 ispositioned to deposit powder 217 in a space created over the topsurfaces of build piece 209 and powder bed 221 and bounded by powder bedreceptacle walls 212. In this example, depositor 201 progressively movesover the defined space while releasing powder 217 from hopper 215.Leveler 219 can level the released powder to form a powder layer 225that has a thickness substantially equal to the powder layer thickness223 (see FIG. 2B). Thus, the powder in a PBF system can be supported bya powder support structure, which can include, for example, a buildplate 207, a build floor 211, a build piece 209, walls 212, and thelike. It should be noted that the illustrated thickness of powder layer225 (i.e., powder layer thickness 223 (FIG. 2B)) is greater than anactual thickness used for the example involving 250 previously-depositedlayers discussed above with reference to FIG. 2A.

FIG. 2D shows PBF system 200 at a stage in which, following thedeposition of powder layer 225 (FIG. 2C), energy beam source 203generates an energy beam 227 and deflector 205 applies the energy beamto fuse the next slice in build piece 209. In various exemplaryembodiments, energy beam source 203 can be an electron beam source, inwhich case energy beam 227 constitutes an electron beam. Deflector 205can include deflection plates that can generate an electric field or amagnetic field that selectively deflects the electron beam to cause theelectron beam to scan across areas designated to be fused. In variousembodiments, energy beam source 203 can be a laser, in which case energybeam 227 is a laser beam. Deflector 205 can include an optical systemthat uses reflection and/or refraction to manipulate the laser beam toscan selected areas to be fused.

In various embodiments, the deflector 205 can include one or moregimbals and actuators that can rotate and/or translate the energy beamsource to position the energy beam. In various embodiments, energy beamsource 203 and/or deflector 205 can modulate the energy beam, e.g., turnthe energy beam on and off as the deflector scans so that the energybeam is applied only in the appropriate areas of the powder layer. Forexample, in various embodiments, the energy beam can be modulated by adigital signal processor (DSP).

The capability to additively manufacture parts enables the manufacturerto generate shapes, configurations, and structures that are notavailable in conventional manufacturing processes. Further, advances inAM technologies are expected to continue. Print speed is continuallyincreasing. 3-D printer form factor has also seen regular advances. Thismeans, among other things, that the area of the build platform ascompared with the size of the component to be printed is becomingprogressively larger as relevant build plates and printer profiles crossunprecedented boundaries in size, speed and sophistication. Theavailability and suitability of candidate materials and chemicalcompounds for use in AM is likewise increasing, meaning that theversatility of AM should continue to positively impact a variety ofmanufacturing applications.

During many AM processes, deposited powder that is not melted or fusedtogether to become part of the structure can manifest itself as loosepowder trapped within the AM structure after the AM process is complete.The trapped powder can interfere with internal functions or features ofthe AM structure and, left unaddressed, the trapped powder can causemore significant problems. For example, the trapped powder can makenoise (e.g., when the AM structure is assembled into a vehicle or othertransport structure, and the AM structure moves due to vibration), addpermanent unnecessary mass to the AM structure, and/or cause thecorresponding AM part to function improperly or to malfunctionaltogether due to the powder's potential to interfere with functionalfeatures (e.g., blocking channels, restricting intended rotational ortranslational motion of parts, saturating clamps and fixtures, etc.).Additionally, to the extent the AM part is assembled as part of a largerstructure, components within the larger structure proximate the affectedAM part also risk adverse effects from loose powder that disperses overtime.

This problem is conventionally addressed via manual fixes at the designstage. After the structure is initially designed as a CAD or other datamodel but prior to AM, practitioners commonly use the CAD software tomanually insert holes in perceived strategic locations of the modeledstructure. The product is then 3-D printed. In a post-processing step,the practitioners attempt to use the holes to facilitate removal of thetrapped powder from features internal to the structure. Themanually-intense nature of this conventional modification of the datamodel can be laborious, especially as the geometric and functionalcomplexity of the structure increases.

This problem can become substantially more complex where, as is usuallythe case, the geometry and the location of the powder holes aredependent on the loading and boundary conditions that may be specifiedfor the component. To determine this information and its potentialeffect on hole design/placement, the designer may conduct a FiniteElement Analysis (“FEA”) test prior to modifying the data model with theinsertion of such holes. FEA tests may determine loading stressesthroughout the structure. Thereupon, holes may be incorporated into thedata model design at points where the test results indicate that theprojected stresses and loads are sufficiently low.

The complexity of the powder hole placement process, and relative timeimposition on the designer, can be substantially greater under certaincircumstances. For example, the stresses on the component as determinedthrough FEA analyses may themselves be significant, thereby limitingpractical and immediately-obvious alternatives for hole placement.Further, time and complexity of the process can be increased where thecomponent includes a relatively large number of internal structuralfeatures that can trap powder, potentially requiring a greater number ofpathways for enabling removal of loose powder. The options otherwiseavailable to designers for placement of holes may be furthercircumscribed by various practical considerations, including for examplea relative absence of gravitational advantages for moving trapped powdertowards intended exit pathways, the lack (or absence) of short andstraightforward available channels/pathways from internal to externalstructural portions, and the like.

Moreover, if a second FEA test (conventionally undertaken aftercompletion of the initial or hole placement) projects additionaldeficiencies, the designer may be relegated to spend more time revisingthe initial hole placements. Reasons for such deficiencies may include,for example, the simulated crossing of stress thresholds or the creationof new stresses due to certain holes inserted for powder removal.Moreover, after each subsequent revision of powder hole placements, thedesigner manually performs an additional FEA analysis to verifystructural integrity. This conventional “trial and error” approach tomanual powder hole placement and modification, based on repeatedlynegative FEA results, is cumbersome, inefficient and more often thannot, fails to provide an optimal solution to a potentially expensiveproblem.

Accordingly, in one aspect of the disclosure, an automated apparatus andprocess for optimizing powder hole placement is presented. Aftercompletion of the AM component design using the data model, a powderfeature insertion process is initiated. In contrast to conventionalapproaches, this automated process uses relevant criteria as precursorsto a tangible analysis. As such, the process tends to produce an optimalyet simple solution to removing trapped powder.

In an exemplary embodiment, a plurality of criteria relating to thecomponent to be 3-D printed and to the 3-D printer itself are received.Based on conclusions determined from these criteria and a relativeweight accorded each conclusion based on, e.g., a reliability of thecriteria in establishing the conclusion and an empirically-derivedimportance of the conclusion, an optimal set of powder removal featuresare determined for use with the component.

Such features include, for example, one or more apertures having aprescribed diameter and one or more powder channels traversing thestructure having a defined geometry. Following an automated verificationof structural integrity, the data model may be updated to incorporatethe identified features. Thus for example, the optimization proceduremay determine a number of apertures, their specific distribution acrossthe data model of the AM component, the diameter and other geometricalattributes (e.g., thickness) of each aperture. The algorithm mayadditionally or alternatively identify one or more powder channels fortransporting powder from the interior of the component to its exterior,and the specific location and geometry of each such channel. In anembodiment, the optimization algorithm includes techniques for providingredundancy and verifying integrity of its conclusions. In anotherembodiment, FEA analyses and related load verification tests areincorporated directly into the procedure. In still another embodiment,information concerning neighboring structures (if any) to the componentmay be considered in the overall analysis to account for both structuralintegrity and an optimization as influenced by design considerations ofsurrounding components.

Powder removal features. Powder removal features according to anembodiment may include apertures (holes) having an appropriate length toaccommodate the thickness of a wall or structure, and having anappropriate diameter to accommodate the sizes of powder particles.Powder removal features may also include a powder channel, which may bea simple aperture of extended length. Alternatively, in someembodiments, a powder channel or powder transport path may be more akinto an arterial system that traverses through a sometimes substantialportion of the component and that may include within it smallerapertures that lead to smaller interior chambers to thereby provide ageneral passage for powder flow to an exterior of the component. Inaddition, in some embodiments, powder pockets or chambers may be createdthat may be configured to collect trapped powder from surrounding areasand provide it to a powder channel. In some configurations, powderpockets and channels may rely on the influence of gravity to enabletrapped powder to flow. In other embodiments, powder channels may relyin part on air flow or suction to move trapped powder along its path.

FIG. 3 illustrates an exemplary embodiment of an apparatus 301 forfacilitating powder removal from AM structures according to an aspect ofthe disclosure. The apparatus 301 includes processing system 304, userinterface 302, display interface 308, and 3-D printer 306. A processingsystem may, for example, include one or more processors or controllerstogether with memory for storing programs and data. For example, theprocessing system may include one or more processors as well as memoryfor storing data and program instructions. The instructions set forth inthe exemplary flowcharts of FIGS. 4A-C, below, or a portion thereof, maybe embodied as code in the memory.

Examples of processors that may be implemented in the processing system304 include microprocessors, microcontrollers, digital signal processors(DSPs), field programmable gate arrays (FPGAs), programmable logicdevices (PLDs), state machines, gated logic, discrete hardware circuits,and other suitable hardware configured to perform the variousfunctionality described throughout this disclosure. One or moreprocessors in the processing system may execute software. Software shallbe construed broadly to mean instructions, instruction sets, code, codesegments, program code, programs, subprograms, software modules,applications, software applications, software packages, routines,subroutines, objects, executables, threads of execution, procedures,functions, etc., whether referred to as software, firmware, middleware,microcode, hardware description language, or otherwise. A processingsystem may include a computer-readable medium.

Accordingly, in one or more exemplary embodiments, the functionsdescribed may be implemented in hardware, software, firmware, or anycombination thereof. If implemented in software, the functions may bestored on or encoded as one or more instructions or code on acomputer-readable medium. Computer-readable media includes computerstorage media. A computer-readable medium may be a discrete storagecomponent, such as a hard drive, or in some configurations it may be aplurality of discrete storage components distributed across multipledevices. Storage media may be any available media that can be accessedby a computer. By way of example, and not limitation, suchcomputer-readable media can comprise random-access memory (RAM),read-only memory (ROM), electronically erasable programmable ROM(EEPROM), compact disk (CD) ROM (CD-ROM), or other optical disk storage,magnetic disk storage or other magnetic storage devices, or any othermedium that can be used to carry or store desired program code in theform of instructions or data structures and that can be accessed by acomputer. Disk and disc, as used herein, includes CD, laser disc,optical disc, digital versatile disc (DVD), and floppy disk where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers. Combinations of the above should also be includedwithin the scope of computer-readable media.

Referring still to FIG. 3, processing system may be coupled to a userinterface 302.

User interface 302 may be included within the same machine 304 in someembodiments, or user interface 302 may be part of a separate device inother embodiments. In the latter case, user interface 302 may be coupledto processing system directly, or through a network such as a Wi-Finetwork, a virtual private network (VPN), an intranet, the Internet, oranother network. These same types of interfaces and network connectionsmay also be employed in the connection between processing system 304 and3-D printer 306, and/or processing system 304 and display interface 308.

In an exemplary embodiment, 3-D printer is coupled to processing system304 via a network. In an alternative embodiment, processing system 304and 3-D printer 306 are part of the same device. Display interface 308may be a separate device from the processing system 304, user interface302, and 3-D printer 306, in which case display interface 308 may besuitably connected to processing system 304 via a network connection, adirect connection, or another suitable means. Alternatively, displayinterface 308 may be part of the same device as user interface 302. Inan exemplary embodiment, user interface 302, processing system 304, anddisplay interface 308 are part of a single computer system coupled to3-D printer 306 via a direct or network connection. In one embodiment,apparatus 301 constitutes a single device. In another embodiment,apparatus 301 constitutes three or less directly connected devices.Other configurations of apparatus 301 or the elements within apparatus301, are possible.

FIGS. 4A-B are a flow diagram illustrating an exemplary process forautomatedly inserting apertures, powder channels and powder chambersinto a data model for removal of powder from an AM structure based onthat model. In one exemplary embodiment, many or most steps of FIGS.4A-C are based directly or indirectly on a design flow that originatesat the innermost portion of the component and terminates at the outsideof the component. That is, the process uses the below-describedinformation and step sequence to evaluate and select channels for powdertransport from an inner portion of the component to an outer portion. Adesign flow according to this embodiment may assist with (i)facilitating easy removal of trapped powder from the inside of thecomponent to its outside, (ii) determining an overall path of leastresistance, which usually means making the smallest necessary structuralchange to the component to accomplish the intended purpose, and (iii)improving further upon the process in the event improvements aredesired.

Referring initially to FIG. 4A, the process may be initiated at step 410when a data model of the component to be 3-D printed is received. Thedata model, which can be a CAD model or any suitable model for use indescribing the component, may include detailed information identifyingeach aspect of the structure and its geometry. Thus, for example, thedata model may include a detailed representation of all internalfeatures potentially contributing to the anticipated trapping of powder.At step 415, to the extent not already provided or otherwise madeavailable by the data model at step 410, the process receives a detailedand comprehensive description of all materials that the component to be3-D printed will include. Also, in an embodiment, the process isprovided access with data that include capabilities and characteristicsof different materials, such as those common for use in a 3-D printer,and the relative advantages and disadvantages of different materials,including different materials used in the same component.

Thereupon, at step 420, the process may receive comprehensive structuraldata concerning the component. In many instances, much or all of thisinformation is provided or made available to the process in connectionwith one or both of steps 410 and 415. To the extent that some, most orall of this information has not been heretofore provided, theinformation may be provided at step 420. This information may includethe loading data, which in turn may include actual data, estimated data,or both. For example, this data may include actual data regarding one ormore stresses or loads asserted by one defined region of the componenton another defined region. The data may further include the load on thecomponent or a defined region thereof as a result of a larger structureif the component is assembled as part of the larger structure. Inalternative embodiments in which loads are not precisely known inadvance, estimated loads may be provided.

The stresses and loads may be defined to included forces having amagnitude and a direction, and thus for sophisticated loads, matricesand/or vectors may be used to describe the various components of theloads including magnitudes and directional components due to specificloads, all loads in total, the gravitational load, etc.

The data received by the process in step 420 may further include knownboundary conditions for each region or border of the component,structural constraints, and other actual or anticipated materialcharacteristics or properties. Such material characteristics orproperties may include, for example, rigidity, thermal expansioncoefficients, stiffness, flexibility, and the like.

As for the above collection of initial steps, it will be appreciatedthat in other embodiments, receipt of all of the identified informationmay not be necessary as accurate determinations may be made with just asubset of the identified information. In still other embodiments inwhich greater sophistication and precision are required, a still greatersubset of this information may be desirable.

At step 425, the process may receive AM or 3-D printer related data. Asin prior steps, some or all of this information may have been providedin connection with the receipt of the CAD model at step 410 or at one ofthe subsequent steps. The printer-specific data may include, forexample, the type of AM process to be used, any materials that will beadded onto the component after the AM process, the size distributions ofthe particles of powder to be used, whether an adhesive will be used ina post-processing step and the relevant details, an identification ofthe support material (if any) to be used in the AM process and theregions where the support material may be present. These specificationsmay, in one embodiment, be relevant to diameter requirements forapertures, capabilities of the 3-D printer to provide aerodynamicprofiles for powder channels, etc.

At step 430, and based in part on information received in prior steps,the process may run an FEA test to determine initial structuralintegrity. This test may be conducted, as in the embodiment shown, as abaseline test of loading and stresses with no powder holes or channelsyet constructed. In some embodiments, alternative variations of the FEAtest may be conducted. After step 430, conclusions reached during theanalyses may be retained for subsequent comparison purposes.

Having received necessary information and conducted an initial REA test,the process may gather component-specific information relevant todetermining which powder removal features are needed. Differentprocedures may be used to accomplish these objectives. In thisembodiment, at step 435, the process identifies the materials andstructures within the component that may be preferred for powder featureinsertion over other materials and structures within the component. Forexample, based on an analysis of the information received including thedata model of the component, the process may first may determine whichmaterials and sub-structures of the component are more amenable tofurther cutting and sculpturing of apertures or channels.

Next, in the same step 435, the process may determine which materialsare thinner that lead to interior areas trapping powder, versusmaterials that are thicker. Generally, the thinner materials will befavored by some predetermined amount over the thicker materials forinserting apertures in the material. By contrast, in another embodiment,the thicker materials that border some interior area may be favored overthe thinner materials for creating a channel. In this exemplaryembodiment, each of these considerations may be given a proportionatepercentage of consideration in determining where to insert apertures. Itis further assumed in some embodiments that when adding holes andchannels for powder removal, the lowest or least intrusive amount ofchange to the structure should be preferred, all else being equal.

In one exemplary embodiment, the process may determine paths for powdertransfer from the inside of the component to the outside to facilitateeasy removal of the trapped powder by identifying a path of leastresistance.

At step 440, the process may identify a hierarchy of regions of thecomponent's data model that are likely to include trapped powder. Theimportance of identifying such regions is that it may not be necessaryto build holes for powder removal in regions without trapped powder. Inan embodiment, the process obtains this information by identifyingsignificant intersecting regions, or regions that include more structure(e.g., more walls), provided that each region has at least one wall orother structural obstacle that tends to keep powder trapped within thoseregions.

Step 440 may also include a search for volumes or regions in thecomponent (i.e., in the data model), such as in a low inset into thecomponent, that may trap powder due to gravity. Thus, if powder isdeemed likely to congregate in a pocket or other region as a result ofgravity, these regions may be identified as potentially requiringfurther powder removal features.

In another exemplary embodiment, the process may search at step 440 forregions that contain material having properties that naturally producemore powder. For instance, it may be the case that certain materials,even when fused, are likely to produce loose powder. For example, thetype and size of the particle of material may be relevant to determiningwhether a powder removal feature is desirable. As another illustration,some regions of the data model may show a large number of finestructures that may be more susceptible to degrading into loose powder.If these conditions are present, they may justify use of powder removalfeatures.

At step 445, the process may identify regions that, in view of theloading and stresses identified at step 430, certain of these regionsmay be more favorable candidates for powder removal features, and otherregions may be less favored. In one exemplary embodiment, the processcombines the data model with the information identified in step 430 andother information as needed. The process may determine that regions notsubject to external loads or that have fewer internal stresses may notrequire powder removal features. It should be noted that in oneembodiment, this information regarding regions not subject tosignificant loads may be combined with step 440 in which regions likelyto include trapped powder were identified. Where a region A is likely toinclude trapped powder (step 440) and where the same region A includesno external loads and few external stresses (step 445), then in theabsence of some other prohibition, region A may be a good candidate forincorporating a powder removal feature at its boundary. By contrast, ifregion A includes no major stresses but also likely has no trappedpowder, an opposite conclusion may be reached. It should be noted thatin general, areas that have significant loads or stresses may beadversely compromised by additional structural changes, and that thisfact may be taken into consideration by the process.

In another embodiment, step 445 may identify regions in the componentthat have moderate external loads and moderate stresses as having a“middle ground”. Thus, the process may define a value for these regionsthat is intermediate between the first case of region A (above) and aregion that exhibits significant difficulty for removal of trappedpowders. In this case, that other steps in the process may ultimately beused to determine whether powder removal features are necessary ordesirable for these regions.

As another example, the process in step 445 may also identify regionsthat have significant loads and weak overall intrinsic supports. Theseregions may be identified as disfavored for employing powder removalpathways.

In an embodiment, the process may take into consideration informationrelating to analogous components or earlier models of the same componentto augment the decision-making process concerning this component. Thus,for example, if at step 445 a region is ruled as disfavored to somemeasurable extent, but that in the prior step 440 the same region wasidentified as requiring a channel for power removal, then the processmay consider “analogous” data from similar 3-D printed structures (e.g.,earlier models of this structure) in rendering a determination. Thisinformation may also include FEA results from prior similar components.

At step 450, the process may identify path features. For example, theprocess may measure from the data model path lengths from powderconcentration areas to areas outside the component. In an embodiment,this information may establish whether an aperture is feasible or, inappropriate cases, where a channel can instead be created to removepowder. Conclusions may be drawn for various applicable regions of thecomponent, and a weight may be accorded each conclusion. The informationfrom this step 450 along with other steps (including, for example step435) may ultimately be used to determine and identify the path(s) ofleast resistance to remove trapped powder from the inside of thecomponent to the outside.

In one embodiment, in addition to path length, the process at step 450may also gather additional information about candidate regions forpowder pockets. A powder pocket is a partially-enclosed region withinthe structure that receives loose powder from other regions as a resultof strategically-placed powder removal features, the geometry of thestructure itself, and/or gravity. In one embodiment, the powder pocketis engraved within the structure. In some embodiments, the complexity ofa structure may mean that a required solution should include one or morepowder pockets that work in conjunction with one or more powder channelsand apertures to transport trapped powder away from as much of theinterior as possible. In this embodiment, the 3-D printing step maysimply be followed by an air flow step through which trapped loosepowder may be eliminated from powder pockets via the powder removalfeatures.

Referring to FIG. 4B, at step 455, the process may identify otherdesired channel or aperture structures. In one embodiment, the processconsiders a given region likely to include loose powder and determineswhat alternatives are available. For example, it is assumed that aparticular wall surrounding a portion of such region was previouslydetermined to be thin enough to suitably accommodate an aperture suchthat trapped powder could be flushed out. It was also determined in asubsequent step, however, that the required diameter of the aperture(set by the size of the loose powder particles) is too large such thatthe structural integrity of the wall would not be adequately sustained.Accordingly, at step 455 in one embodiment, different alternatives maybe considered to remove loose powder from that region. For example,another wall surrounding another portion of the region at issue may alsobe analyzed for this purpose. In addition, assuming this other wall isfound to have the requisite structural integrity to accommodate thediameter of an aperture, it may be determined whether an aperture inthat wall would lead from the region at issue to a pathway exterior tothe component to allow removal of the trapped powder.

If the wall is found not to satisfy these criteria for the region atissue, it may next be determined whether other alternatives areavailable. For example, the process may consider an increased air flow,a suction mechanism, gravitational assistance, and/or use of anotherpathway. All of these factors may be considered and relatively weighed.In an embodiment, if all choices result in non-ideal solutions, theoption that includes the least structural compromise may be selected.

At step 458, degrees of assistance for powder removal are prioritized,if more than one option is available. In an embodiment, pathways (e.g.,channels and apertures) for which powder flow is facilitated mainly bythe influence of gravity are the most favored. Powder removal requiringpositive air flow and/or suction may be the second-most favored.Movement or other manipulation of the part may be the third-mostfavored, and so on. Then other alternative feature types may also benarrowed down. Shorter paths are favored over longer ones. Additionally,certain configurations may favor others. For example, a single, longpowder channel with aerodynamic contour may be favored over three shortpowder channels, one of which lack a contour. Rules that favor ordisfavor alternatives can be programmed into the algorithm and changedperiodically or on the fly.

At step 460, determinations are finalized, alternatives are compared andweighed. The process applies its rules using the information itinitially acquired as a result of programming, and the additionalknowledge the process acquires through analysis of the data model todetermine a set of one or more apertures, powder channels, and/or powderchambers. An air flow path, if required, may be designated. An order forusing the paths, if required, may also be designated. The location andtype of all powder removal features are designated. Step 460 in oneembodiment applies the changes directly to the data model, such as byupdating the CAD program to incorporate the apertures and contouredpowder channels.

In an embodiment, the process at step 460 also evaluates and selectschannels for powder transport from an inner portion of the component toan outer portion to facilitate easy removal of trapped powder and todetermine an overall path of least resistance.

At step 465, the FEA test or a similar structural analysis is rerun.Upon non-ideal solution (468), the process attempts to resolve thefailed areas by removing the offending or problematic apertures orchannels from the model (step 479). Control then returns to step 435,where the process reruns its conclusion and determination efforts inlight of the new FEA data and the new removal of the perceived problempaths. In this embodiment, the entire process may be run from step 435onward to enable a new solution (affirmatively excluding the lastsolution) to be identified.

If, by contrast, the FEA test succeeds, the process at step 470 may runa powder removal simulation. Unlike a test in which the loads andstructural integrity of the component are assessed, this test maysimulate the effectiveness of the chosen pathway in removing trappedpowders. The required parameters for this test may vary widely dependingon the configuration. In one exemplary embodiment, the simulation mayendeavor to identify an alternative path, if one exists, that is simpler(i.e., requires fewer paths and apertures, etc.) than the path beingused. If the simulation produces non-ideal results, the process mayidentify the point of failure, after which it may remove the perceivedfailure point from the model and return control back to step 435. Atstep 465, the process may be rerun with the new inputs. If thesimulation is successful (468), the optimization is complete (480).

FIG. 5 is an view of an exemplary AM structure 500 having powder removalfeatures. AM structure 500 is a structure produced from a data modelusing a PBF technique. The structure 500 may include a powder reservoir502 designed by the optimization routine. A powder reservoir, alsoreferred to as powder chamber, is a region designated for the loosepowder to be stored. The powder reservoir 502 may serve as an inlet oroutlet for the movement of powder. In this example, powder mayaccumulate in powder reservoir 502, from which it may travel through apowder channel such as powder channel 504 via the influence of gravity,suction, etc. Powder channel 504 may lead to powder hole 506. which isconnected in this example to a large hollow area defined by cylindricalregion 508. A side of hollow cylindrical region 508 may be open to anoutside of the structure 508. Loose powder can easily be channeled toregion 508 and then outside the part.

The methods described in the above description may be effectuated by acomputer or other processing system as described with reference to FIG.3, above. In some configurations, the techniques described herein may beperformed separately by a computer or by a computer or other processingsystem coupled to or otherwise integral to the 3-D printer system. Insome embodiments involving the 3-D printer as a fully functionalintegrated system, a computer or processing system may be built into thesystem or coupled to the system, whether networked or in the same systemor functional set of components.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these exemplary embodiments presented throughout thisdisclosure will be readily apparent to those skilled in the art, and theconcepts disclosed herein may be applied to other techniques forprinting nodes and interconnects. Thus, the claims are not intended tobe limited to the exemplary embodiments presented throughout thedisclosure, but are to be accorded the full scope consistent with thelanguage claims. All structural and functional equivalents to theelements of the exemplary embodiments described throughout thisdisclosure that are known or later come to be known to those of ordinaryskill in the art are intended to be encompassed by the claims. Moreover,nothing disclosed herein is intended to be dedicated to the publicregardless of whether such disclosure is explicitly recited in theclaims. No claim element is to be construed under the provisions of 35U.S.C. § 112(f), or analogous law in applicable jurisdictions, unlessthe element is expressly recited using the phrase “means for” or, in thecase of a method claim, the element is recited using the phrase “stepfor.”

What is claimed is:
 1. A method for automatedly inserting powder removalfeatures in an additively manufactured component, the method comprising:receiving a model of a component to be additively manufactured;automatedly determining optimal size and location of one or moreapertures in the component for powder removal; and updating the model toinclude the one or more determined powder removal apertures.
 2. Themethod of claim 1, further comprising additively manufacturing thecomponent based on the updated model.
 3. The method of claim 2, furthercomprising removing trapped powder from the additively manufacturedcomponent using the one or more powder removal apertures.
 4. The methodof claim 1, wherein the automatedly determining optimal size andlocation of the one or more apertures comprises evaluating potentialgravitational advantages for facilitating powder removal.
 5. The methodof claim 1, wherein the automatedly determining optimal size andlocation of the one or more apertures comprises selecting an aperturesize based at least in part on a type of material to be used as powderparticles in the additive manufacturing of the component.
 6. The methodof claim 1, wherein the automatedly determining optimal size andlocation of the one or more apertures comprises evaluating loading andboundary conditions for the component.
 7. The method of claim 1, furthercomprising automatedly determining geometry and location of one or morepowder channels for removing powder after additively manufacturing thecomponent.
 8. The method of claim 7, wherein the automatedly determininggeometry and location of the one or more powder channels comprisesidentifying a shortest removal path.
 9. The method of claim 7, whereinthe automatedly determining geometry and location of the one or morepowder channels comprises identifying a path of least materialresistance.
 10. The method of claim 7, wherein the automatedlydetermining geometry and location of the one or more powder channelscomprises evaluating potential gravitational advantages for facilitatingpowder removal.
 11. The method of claim 1, wherein the automatedlydetermining optimal size and location of the one or more aperturescomprises specifying an aerodynamic contour for the aperture tofacilitate subsequent powder removal through air flow.
 12. The method ofclaim 7, wherein the automatedly determining geometry and location ofthe one or more powder channels comprises specifying an aerodynamiccontour for the one or more powder channels to facilitate subsequentpowder removal through air flow.
 13. The method of claim 1, wherein theautomatedly determining optimal size and location of the one or moreapertures comprises evaluating at least one of powder material, powderparticle size distribution, average powder flow rate, and powder type.14. The method of claim 7, wherein the automatedly determining size andplacement of the one or more powder channels comprises evaluating atleast one of powder material, powder particle size distribution, averagepowder flow rate, and powder type.
 15. A method for removing powder froman additively manufactured component having at least one aperture,comprising: receiving a data model of the component; additivelymanufacturing the component based on the data model; removing trappedpowder from the additively manufactured component using the at least oneaperture; and performing a layup process using at least one material toseal the aperture.